With the development of LED display industry, the LED display screens are widely used in more and more occasions such as advertisement, traffic, dispatch center, shows and rally. However, these display screens more or less have the problem of non-uniform display such as mosaic caused by deviation/difference of luminance and/or chrominance between LED dots, and thus it is necessary to calibrate each LED dot with the help of image acquisition apparatus so as to make the displays of the LED display screens are as smooth as mirror.
A LED cabinet calibration generally is carried out in the factory, and thus the cost of manpower and material is relatively small. Nowadays, display screen manufacturers tend to adopt the cabinet calibration, this is because the cabinet calibration can make the LED display be uniform before leaving the factory and can save the manpower compared with the on-site calibration. The cabinet calibration can significantly improve the luminance and chrominance evenness/uniformity in each cabinet and between cabinets, and eliminate a bright/dark line in each cabinet as well as a splicing bright/dark line between cabinets, and thus can guarantee the display uniformity when all the LED cabinets are assembled randomly on site.
With dramatic increase of orders of the LED display screen manufacturers, higher efficiency is needed by the LED display screen manufacturers for cabinet calibration before leaving the factory. However, the existing cabinet calibration is time-consuming and requires a lot of labor, and therefore it is difficult to meet the requirements of a large number of shipments for the display screen manufacturers.
FIG. 1 is a conventional architecture for luminance and chrominance calibration of LED cabinet (or termed as cabinet calibration) in the factory and including an image acquisition apparatus 11 (such as a camera), a calibration computer 13, a LED controller 15 and a to-be-calibrated LED cabinet 30. A concrete luminance-chrominance calibration process is that: (a) manually placing the LED cabinet 30 onto a preset position and connecting the LED cabinet 30 to the LED controller 15 and the calibration computer 13; (b) using the calibration computer 13 to control the LED controller 15 to sequentially play red, green and blue color images and to control the image acquisition apparatus 11 to sequentially collect luminance and chrominance information of the red, green and blue color images; (c) the calibration computer 13 calculates luminance and chrominance information of red, green and blue LED dots according to the collected luminance and chrominance information and generates calibration coefficients of corresponding LED dots; (d) using the LED controller 15 to upload the calibration coefficients to the LED cabinet 30 for storing; and (e) then the luminance-chrominance calibration of the LED cabinet 30 is finished; and after that, manually removing the calibration-finished LED cabinet 30, placing next LED cabinet to the preset position and repeating the above steps (a), (b), (c) and (d).
From the foregoing discussion, it can be understood that in the conventional LED cabinet calibration method in the factory, the LED cabinet is manually placed onto the preset position, if the placed position and the preset position have an offset existed therebetween, which will affect the data acquisition/collection for the LED cabinet; moreover, it cannot perform image acquisition simultaneously to multiple LED cabinets; and in addition, it needs two persons for carrying the cabinet and one calibration operation person, the co-working of three persons leads to the manual calibration being time-consuming.